1. Field of the Invention
The present disclosure relates to an organic light emitting diode display, and more particularly, to an organic light emitting diode display which is capable of preventing a driving switching element from being deteriorated.
2. Discussion of the Related Art
Recently, various flat panel displays which are small and low in weight compared with a cathode ray tube have been developed, and a light emitting display which has a high luminous efficiency, excellent brightness, wide viewing angle and high response speed, among the flat panel displays, has been especially highlighted.
A light emitting element has a structure where a light emitting layer, which is a thin film emitting light, is disposed between a cathode electrode and an anode electrode, and a characteristic where excitons are generated in the light emitting layer by injecting electrons and holes into the light emitting layer and recombining them therein and light is emitted from the light emitting layer when the generated excitons falls to their low energy states.
The light emitting layer of the light emitting element is composed of an inorganic material or organic material, and the light emitting element is classified into an inorganic light emitting element and an organic light emitting element according to the material type of the light emitting layer.
The level of driving current flowing to the light emitting element has a large deviation depending on a threshold voltage of a driving switching element provided in each pixel. Because driving switching elements of respective pixels have different threshold voltage characteristics due to a manufacturing characteristic of an organic light emitting diode display, driving currents flowing through the driving switching elements of the respective pixels may have different values in spite of the same data voltage, resulting in a problem that a picture quality may be degraded due to brightness differences among light emitting elements of the respective pixels.
Further, because a positive data voltage is continuously supplied to the gate electrode of the driving switching element, the driving switching element may be subject to a severe deterioration, resulting in a problem that the threshold voltage of the driving switching element may vary.